This invention relates to hatch covers of railway cars.
In U.S. Pat. No. 3,228,353, a hatch cover strap is pivotably mounted on a rail car roof and supports a round hatch cover for pivotal movement between open and closed positions. A stud is attached to the center portion of the cover which passes through an opening in the strap. A nut holds the cover in engagement with the strap. This patent also discloses (FIG. 4) hatch cover pivotably mounted upon the car roof and having three hand operated screw-down latches located 120.degree. apart on the cover. In recent arrangements step-down, over-center latches have been substituted for these hand operated latches. See, for example, ACF Shippers Car Line Brochure No. SHPX-CF-9 7/66 (copy in application file) which discloses a round hatch with a similar strap and an over-center latch arrangement.
In U.S. Pat. No. 3,307,498, straps are attached to an elongated cover with fastening studs, and an over-center locking lever is used to hold the strap in closed position.
U.S. Pat. Nos. 2,8l6,683 and 3,760,743 also disclose hatch cover straps in which step-on, over-center latches hold the covers in closed position in transit.
All of the above references are hereby incorporated into the present application by this reference.